As a rule, the pressure of the air suspension compressor of Rover Sport is about 18 atmospheres.

Usually, there are not problems with electric or air wiring of air suspension systems on Land Rover Discovery (Discovery 3) cars.

The two most likely causes are:

• Either the relay is jammed (soldered contacts), then even with the engine shut off, the compressor will work. In this case, you must either remove the battery terminal; remove the compressor fuse or remove the relay itself to turn off the compressor;
• Maybe compressor is dead. But then the system should give an error. Because, as practice has shown, if the compressor is working and there is no pressure, after a certain time the compressor will turn off and error appears.

The first thing you can do is to connect a monometer to the compressor and start the compressor by applying a voltage of 12 volts to it, to check how much pressure it creates. At the same time, you can check the suspension compressor for leaks at the joints with suspension lines and the dryer with the help of a soap mix.

In Land Rover/Range Rover Sport, Land Rover Discovery and Range Rover cars, they install Hitachi suspension compressor and in Land Rover Vogue – a Wabco compressor is installed. In Hitachi compressors, the dehydrator cover often breaks, so part of the air comes out of the suspension system and the necessary pressure is not created in a result of that. The problem is solved by replacing the cover of the dryer. You can order the original cover, and you can install a more reliable thickened cover on the service station.

Land Rover Vogue / Land Rover Range Rover air suspensions in any case need to be poured with soapy water at the bend at the very bottom of the suspension where the rubber rolls onto the piston and see if bubbles appear. If possible, you should also check for leaks using a soap solution through pneumatic lines, which are connected to the suspension. Of course, full diagnostics and testing of the air suspension can be done at the service station.

At the service station, there is an opportunity to exclude the entire pneumatic system by disconnecting the pneumoline from the suspension which being diagnosed, connect to an external system, pump it up and leave, for example, overnight. Before this, of course, the height is measured. If, in the morning, car has «fell down», then definitely there’s problem in the suspension. If the position of the air suspension remains unchanged, then the problem is somewhere in the system.